look up any word, like bukkake:
 
1.
The head of a mans dick
Can you make my mushroom helmet touch your tonsils?
by smitty December 20, 2002
 
2.
The end part of a mans penis which is so hardand sore it eventually looks like a mushroom.
Me -"CRIST! Look at that germans bell!"
My bro -"Mushroom helmet!"
*everyone watching german porn laughs*
by GirlSkater May 02, 2004